president obama calls off a meeting with vladimir putin as tensions rise over nsa leaker edward snowden. how have past presidents dealt with russia. >> and could the mystery of the mona lisa finally be solved? >> this a great story. new research put a name to the famous face after they dug through a tomb. >> president obama cancelled a planned summit with the russian president vladimir putin in response russia's government refusing to send edward snowden back to the united states. not only is he not going to meet with hill. is he sending joe biden. ♪ [ man ] 5, 4... [ command center ] this is command center. [ man ] ...3, 2, 1. [ command center ] all systems go. [ female announcer ] introducing swiffer steamboost powered by bissell. steam-activated cleaning pads penetrate deep. [ command center ] we have lift off. [ female announcer ] don't just clean your floor. boost it. [ female announcer ] don't just clean your floor. ...and a great deal. grrrr! ahhh! let's leave the deals to hotels.com. perfect! yep, and no angry bears. up to 40% off. only at hotels.com (tires screeching) red hot